A morphological study of the posterior communicating artery.

This study aims to identify and yield a better understanding of the origin of the posterior communicating artery, its perforating branches and the relations in the vicinity of that artery. In 30 brains filled with a mixture of latex through the internal carotid and basilar arteries the posterior communicating artery originated from the posterior aspect of the C4 part of the internal carotid artery in 20 hemispheres (66.6%) and from its postero-lateral part in 8 hemispheres (26.6%). In 2 hemispheres (6.6%), however, it originated from the anterior aspect of the internal carotid artery. In 8 hemispheres (26.6%) a foetal type of posterior communicating artery was observed. It was 11.94 mm (8.03-15.07 mm) in length from the origin of the PCoA to the point of union with the posterior cerebral artery. The PCoA gave 5, 8 perforating branches (4-9). The distance of the origin of these branches from the origin of the PCoA was 3.30 mm (0.06-9.05) and the area occupied by the origins of the perforating branches was 4.53 mm (0.01-9.07). The perforating branches of the posterior communicating artery were generally dense in the initial 2/3 of the artery. Consequently, the posterior third of the posterior communicating artery seems to be a safer area during surgical operations. As the perforating branches are dense in the initial 2/3 of the artery, this region is at highest risk of damage during operations.